The present invention relates to a leader block assembly for a data storage tape cartridge. More particularly, it relates to a leader block configured for preventing leader block impressions on data storage tapes.
Data storage tape cartridges have been used for decades in the computer, audio, and video fields. The data storage tape cartridge continues to be an extremely popular form of recording large volumes of information for subsequent retrieval and use.
A data storage tape cartridge generally consists of an outer shell or a housing maintaining at least one tape reel assembly and a length of magnetic storage tape. The storage tape is wrapped about a hub portion of the tape reel and is driven through a defined tape path by a driving system. The housing normally includes a separate cover and a base, the combination of which forms an opening (or window) at a forward portion thereof for allowing access to the storage tape by a read/write head upon insertion of the data storage tape cartridge into a tape drive.
In a reel-to-reel magnetic tape drive, a free end of the storage tape is directed away from the housing of the data tape cartridge to an adjacent area at which the read/write head is located. The free end of the storage tape of the data tape cartridge is typically secured to a leader block for assisting guidance of the storage tape. In particular, the leader block is removably inserted into a drive take-up reel (separate from the data storage tape cartridge) and the storage tape from the cartridge is wound about the drive take-up reel as data is accessed/recorded from the tape by the adjacent read/write head.
As shown in FIGS. 1-2, a conventional leader block 10 includes a generally rectangular body 12 defining a trailing end 14 and a leading end 16. The trailing end 14 terminates in an end surface 18. Prior art leader block 10 further includes opposite sides 20 and edges 21 with T-shaped protrusions 22 configured for reciprocally engaging a slot of a drive take up reel to removably secure the leader block 10 relative to the drive take-up reel.
As shown in FIG. 3, a conventional drive take-up reel 30 includes a ringshaped hub 32 and opposing flanges 34. The hub 32 defines a tape-winding surface 36, about which the storage tape (not shown) is wound, and a slot 38. The slot 38 is adapted for receiving the leader block 10. The flanges 34 define a pair of notches 40 contiguous with the edges of the slot 38 for receiving the protrusions 22 of the leader block 10. As further shown in FIG. 4, the slot 38 is defined by opposing sidewalls 41, while the notch 40 of each flange 34 further includes a shelf 42 and a channel 44.
During use, the leader block 10 is inserted into the slot 38 of the drive take-up reel 30, with the opposite sides 20 of the leader block 10 being slidingly received by sidewalls 41 of the slot 38 of the take-up reel 30. Upon further insertion of the leader block 10, the T-shaped protrusions 22 are supported by the shelf 42 of the notches 40 to resist further sliding movement of leader block 10 radially inward relative to the slot 38. This interaction attempts to maintain the end surface 18 of the leader block 10 in a generally flush relationship with the tape-winding surface 36 of the drive take-up reel 30. Accordingly, all of the radial support for the leader block 10 occurs at the notches 40 of the flanges 34 at the edges of hub 32 (see FIG. 3).
Following insertion, the data storage tape (not shown) is wound about the hub 32. In theory, a radius of the end surface 18 of the leader block 10 "matches" a radius of the hub 32. However, as the amount of wrapped tape increases, a substantial pressure is exerted radially inward on the leader block 10, causing a significant middle portion of the end surface 18 to bow or sag radially inward relative to the tape-winding surface 36. This sagging occurs because the notches 40 provide relatively little radial support for the leader block 10. This sagging results in a mismatch or a gap between the end surface 18 of the leader block 10 and the tape-winding surface 36. As the data storage tape is further wound about the hub 32, the storage tape is forced into or fills the gap, creating impressions in the storage tape (or "leader block impressions"). These leader block impressions may reduce the storage capacity of the data storage tape, and possibly permanently damage the storage tape.
The ability of a leader block to remain properly seated into a drive takeup reel has a very large affect on likelihood of the leader block impressions and their transfer through the storage tape. If these leader block impressions are severe, they will transmit through many feet of tape, reducing the data transfer and storage capacity of the cartridge. Currently, to overcome the problem of leader block impressions, more tape is added to the data tape cartridge and drive software is programmed to move the start of data transfer away from the beginning of the tape (at which leader block impressions are most prevalent). Advancements in storage tape media have resulted in highly thin tape.
The decreased thickness tape is even more susceptible to any winding surface mismatch and the ensuing leader block impressions that transfer through the tape wound on the drive take-up reel. Accordingly, the longstanding problem of leader block impressions in data storage tape threatens to nullify the gains obtained by recently available, thinner storage tapes. Moreover, the problem of leader block impressions still requires remedial adjustments such as software changes and intentionally not using portions of the data storage tape.
Data storage tape cartridges are important tools used to maintain vast amounts of information. To remain competitive, data storage tape cartridge manufacturers must continually improve cartridge performance while reducing manufacturing costs. Solving leader block impressions in data storage tapes remains a challenge.